The dramatic impacts of extreme weather conditions and the international negotiations on how to reduce emissions of greenhouse gases keep climate change at the forefront of the news. There seems to have been a shift in the way we discuss climate change, from talking about it as something that will happen a long way in the future to something that has happened already and is happening now.
The latest report from the International Panel on Climate Change states that based on the 2010s, global temperature has already increased by 1.1°C since the pre-industrial period. We are, therefore, already most of the way to reaching the global warming limit of 1.5°C, a level that many scientists consider a dangerous climate threshold.
Changes in temperature and other climatic factors have a direct influence on all types of plants in managed and unmanaged environments. One well-known example of changes in crop distribution linked to climate change is the increasing area of grapevines in the UK, which doubled between 2014-2022.
As well as influencing where plants survive, climate change affects the phenology of plants, that is, the time of year at which different life stages occur, such as the first leaves opening or flowering.
Weather and climate also affect the health of plants by influencing plant pathogens and invertebrate pests.
One strain of the bacterial plant pathogen, Xylella fastidiosa, is responsible for the devasting disease called Olive Quick Decline Syndrome, which has damaged tens of thousands of hectares of olive groves in the south of Italy. Some strains of Xylella are known to be vulnerable to cold conditions in winter via a process called ‘winter curing,’ and this can restrict their distribution. However, increasingly mild winters are shifting the area where winter curing is effective further north.
With a few exceptions, insects are nearly all ectothermic. This means they are reliant on external environmental factors, especially temperature, in order to regulate their internal temperature. Their internal temperature has a direct link with their rate of development, reproduction, and activity. The climate warming that has happened already has aided the establishment or re-establishment of some insect species in the UK.
Increasing populations of some other insects are less welcome. Diamondback moths are pests of brassica crops. They arrive in the UK as migrants during warmer months, and subsequent generations can cause widespread damage to crops. There is evidence that this moth has overwintered in the UK, and with increasingly milder winters, there is potential for greater populations and damage in the future.